September weather forecastSullivan, NH
September
Weather in September
September, the first month of the autumn in Sullivan, is still a pleasant month, with an average temperature fluctuating between 70°F (21.1°C) and 50.9°F (10.5°C).Temperature
As August shifts into September, a minor alteration in temperatures is observed, with average highs reducing from a warm 78.1°F (25.6°C) to a pleasant 70°F (21.1°C). In the month of September, the nighttime temperature dips to a steady average of 50.9°F (10.5°C).Humidity
The average relative humidity in September is 79%.Rainfall
In Sullivan, during September, the rain falls for 9.3 days and regularly aggregates up to 0.79" (20mm) of precipitation. In Sullivan, during the entire year, the rain falls for 125.1 days and collects up to 11.69" (297mm) of precipitation.Snowfall
In Sullivan, snow does not fall in June through September.Daylight
In Sullivan, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:14 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:45 am and sunset at 6:31 pm EDT.
Sunshine
In September, the average sunshine is 8.5h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: The daily maximum UV index of 4 in September interprets into the following advice:
Take necessary precautions - Protection from skin and eye injury is mandatory. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Sullivan, NH
- Average high temperature in September: 70°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (27.9°F).
- Average low temperature in September: 50.9°F
The month with the highest average low temperature is July (58.6°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).
Average pressure in September
Sullivan, NH
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Sullivan, NH
- Average wind speed in September: 5.4mph
The windiest months (with the highest average wind speed) are January, February and March (7.9mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in September
Sullivan, NH
- Average humidity in September: 79%
The month with the highest relative humidity is February (85%).
The month with the lowest relative humidity is April (74%).
Average rainfall in September
Sullivan, NH
- Average rainfall in September: 0.79"
The wettest month (with the highest rainfall) is July (1.3").
The driest month (with the least rainfall) is March (0.75").
Average rainfall days in September
Sullivan, NH
- Average rainfall days in September: 9.3 days
The month with the highest number of rainy days is May (14.6 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Sullivan, NH
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.64").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Sullivan, NH
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (9.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Sullivan, NH
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 30min
The month with the most sunshine is August (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 24min).
Average sunshine days in September
Sullivan, NH
- Average sunshine days in September: 17.2 days
The month with the most sunshine days is November (20.2 days).
The month with the least sunshine days is May (13.8 days).
Average UV index in September
Sullivan, NH
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Sullivan, NH
- Average cloud cover in September: 38
The months with the most cloud cover are February and March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 35).
Average visibility in September
Sullivan, NH
- Average visibility in September: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October, November and December (5mi).





